scholarly journals Studies on mitochondrial structure and function in Physarum polycephalum. V. Behaviour of mitochondrial nucleoids throughout mitochondrial division cycle.

1977 ◽  
Vol 72 (3) ◽  
pp. 687-694 ◽  
Author(s):  
T Kuroiwa ◽  
S Kawano ◽  
M Hizume
Keyword(s):  
Physarum Polycephalum ◽  
Mitochondrial Membrane ◽  
Light And Electron Microscopy ◽  
Structure And Function ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Division ◽  
Mitochondrial Structure ◽  
Mitochondrial Nucleoids ◽  
And Function ◽  
Narrow Bridge

The fine structure of mitochondria and mitochondrial nucleoids in exponentially growing Physarum polycephalum was studied at various periods throughout the mitochondrial division cycle by light and electron microscopy. The mitochondrial nucleoid elongates lingitudinally while the mitochondrion increases in size. When the nucleoid reaches a length of approximately 1.5 mum the mitochondrial membrane invaginates at the center of the mitochondrion and separates the mitochondrial contents. However, the nucleoid does not divide even when the mitochondrial sections are connected by a very narrow bridge. Just before division of the mitochondrion, the nucleoid divides by constriction of the limiting membrane of the dividing mitochondrion. After division, one end of the nucleoid appears to be associated with the inner mitochondrial membrane. The nucleoid then again becomes situated in the center of the mitochondrion before repeating these same processes.

scholarly journals Transmembrane BAX Inhibitor-1 Motif Containing Protein 5 (TMBIM5) Sustains Mitochondrial Structure, Shape, and Function by Impacting the Mitochondrial Protein Synthesis Machinery

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2147
Author(s):  
Bruno Seitaj ◽  
Felicia Maull ◽  
Li Zhang ◽  
Verena Wüllner ◽  
Christina Wolf ◽  
...  
Keyword(s):  
Cell Death ◽  
Protein Synthesis ◽  
Mitochondrial Membrane ◽  
Mitochondrial Protein ◽  
Mitochondrial Protein Synthesis ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Structure ◽  
Protein Synthesis Machinery ◽  
Atp Generation ◽  
And Function

The Transmembrane Bax Inhibitor-1 motif (TMBIM)-containing protein family is evolutionarily conserved and has been implicated in cell death susceptibility. The only member with a mitochondrial localization is TMBIM5 (also known as GHITM or MICS1), which affects cristae organization and associates with the Parkinson’s disease-associated protein CHCHD2 in the inner mitochondrial membrane. We here used CRISPR-Cas9-mediated knockout HAP1 cells to shed further light on the function of TMBIM5 in physiology and cell death susceptibility. We found that compared to wild type, TMBIM5-knockout cells were smaller and had a slower proliferation rate. In these cells, mitochondria were more fragmented with a vacuolar cristae structure. In addition, the mitochondrial membrane potential was reduced and respiration was attenuated, leading to a reduced mitochondrial ATP generation. TMBIM5 did not associate with Mic10 and Mic60, which are proteins of the mitochondrial contact site and cristae organizing system (MICOS), nor did TMBIM5 knockout affect their expression levels. TMBIM5-knockout cells were more sensitive to apoptosis elicited by staurosporine and BH3 mimetic inhibitors of Bcl-2 and Bcl-XL. An unbiased proteomic comparison identified a dramatic downregulation of proteins involved in the mitochondrial protein synthesis machinery in TMBIM5-knockout cells. We conclude that TMBIM5 is important to maintain the mitochondrial structure and function possibly through the control of mitochondrial biogenesis.

Abstract 15070: Micu1 Regulates Mitochondrial Cristae Structure and Function Independent of the Mitochondrial Calcium Uniporter Channel

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Dhanendra Tomar ◽  
Manfred Thomas ◽  
Joanne Garbincius ◽  
Devin Kolmetzky ◽  
Oniel Salik ◽  
...  
Keyword(s):  
Mitochondrial Membrane ◽  
Coiled Coil ◽  
Structure And Function ◽  
Membrane Dynamics ◽  
Size Exclusion ◽  
Null Mouse ◽  
Intermembrane Space ◽  
Inner Mitochondrial Membrane ◽  
Cytochrome C Release ◽  
And Function

Background: MICU1 is an EF-hand domain containing Ca 2+ -sensor regulating the mitochondrial Ca 2+ uniporter channel and mitochondrial Ca 2+ uptake. MICU1-null mouse and fly models display perinatal lethality with disorganized mitochondrial architecture. Interestingly, these phenotypes are distinct from other mtCU loss-of-function models ( MCU, MICU2, EMRE, MCUR1 ) and thus are likely not explained solely by changes in matrix Ca 2+ content. Using size-exclusion proteomics and co-immunofluorescence, we found that MICU1 localizes to mitochondrial complexes lacking MCU. These observations suggest that MICU1 may have additional cellular functions independent of the MCU. Methods: Biotin-based proximity labeling and proteomics, protein biochemistry, live-cell Ca 2+ imaging, electron microscopy, confocal and super-resolution imaging were utilized to identify and validate MICU1 novel functions. Results: The expression of a MICU1-BioID2 fusion protein in MCU +/+ and MCU -/- cells allowed the identification of the total vs. MCU-independent MICU1 interactome. LC-MS analysis of purified biotinylated proteins identified the mitochondrial contact site and cristae organizing system (MICOS) components Mitofilin (MIC60) and Coiled-coil-helix-coiled-coil helix domain containing 2 (CHCHD2) as MCU independent novel MICU1 interactors. We demonstrate that MICU1 is essential for proper organization of the MICOS complex and that MICU1 ablation results in altered cristae organization, mitochondrial ultrastructure, mitochondrial membrane dynamics, membrane potential, and cell death signaling. We hypothesize that MICU1 is a MICOS Ca 2+ - sensor since perturbing MICU1 is sufficient to modulate cytochrome c release independent of Ca 2+ uptake across the inner mitochondrial membrane. Conclusions: Here, we provide the first experimental evidence of an intermembrane space Ca 2+ - sensor regulating mitochondrial membrane dynamics, independent of changes in matrix Ca 2+ content. This study provides a novel paradigm to understand Ca 2+ -dependent regulation of mitochondrial structure and function and may help explain the mitochondrial remodeling reported to occur in numerous disease states.

scholarly journals Effects of Carbonyl-cyanide m-chlorophenylhydrazone on Mitochondrial Function of H9C2 Cells

2017 ◽  
Author(s):  
Ngo Thi Hai Yen ◽  
Bui Thi Van Khanh ◽  
Vu Thao Hien ◽  
To Thanh Thuy ◽  
Pham Thi Bich ◽  
...  
Keyword(s):  
Mitochondrial Function ◽  
Mitochondrial Membrane ◽  
Membrane Lipids ◽  
Structure And Function ◽  
Intensity Change ◽  
H9c2 Cells ◽  
Mitochondrial Structure ◽  
Carbonyl Cyanide ◽  
And Function ◽  
Fluorescence Intensity Change

We examined the effects of carbonyl-cyanide m-chlorophenylhydrazone (CCCP) on mitochondrial function of H9C2 cells. Composition of mitochondrial membrane lipids (cardiolipin) and mitochondrial membrane potential was analyzed by fluorescence intensity change of tetramethl rhodamine ethyl ester (TMRE) and 10-nonyl acridine orange (NAO) using the LSM800 confocal microscope. Our results showed that CCCP strongly and simultaneously affected mitochondrial structure and function of H9C2 cells.

scholarly journals Aluminum Impairs Rat Neural Cell Mitochondria In Vitro

2005 ◽  
Vol 18 (4) ◽  
pp. 683-689 ◽  
Author(s):  
P.Y. Niu ◽  
Q. Niu ◽  
Q.L. Zhang ◽  
L.P. Wang ◽  
S.C. He ◽  
...  
Keyword(s):  
Mitochondrial Membrane ◽  
Cell Function ◽  
Structure And Function ◽  
Neural Cells ◽  
Oxygen Species ◽  
Mitochondrial Ultrastructure ◽  
Cell Death Rate ◽  
Mitochondrial Structure ◽  
And Function

Exposure to aluminum has been reported to lead to neurotoxicity. Mitochondria are important organelles involved in maintaining cell function. This study investigates the effect of aluminum on mitochondria in rat neural cells. The ultrastructure of mitochondria was observed, and the cell death rate (CDR), reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and 3-[4,5demethyl-2-thiazalyl]-2,-5diphenyl-2H-tetrazolium bromide (MTT) were measured to investigate the effect of aluminum on the mitochondrial structure and its function in neural cells. Results observed from the mitochondrial ultrastructure show that aluminum may impair the mitochondrial membrane and cristae. Increased CDR, enhanced ROS, decreased MMP, and decreased enzyme activity in mitochondria were observed in the Al-exposed neurons (100 – 500 μM). The present study demonstrates that alteration in the mitochondrial structure and function plays an important role in neurotoxic mechanisms induced by aluminum.

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